The present invention is used in the field of automated analysis where liquids are pipetted with pipettes and fluids are stirred with stirrers as necessary.
The present invention provides a device for cleaning pipette probes or stirrers, comprising                a cavity that holds cleaning fluid and whose lower region has a fluid duct for filling and/or emptying the cavity, and        at least one inlet tube which empties into at least one nozzle directed toward the interior of the cavity.        
When sample fluids such as blood or urine are analyzed, they must be pipetted into containers along with any necessary wash fluids, reagents, etc. The pipette must be rinsed between pipettings to avoid carryover between consecutive samples or reagents. If fluids must be mixed in automated analyzers, this is usually performed using stirrers that are lowered into the sample fluid. The stirrer must be cleaned between each step in the mixing procedure to avoid carryover of the material to be mixed by the stirrer. Examples of materials to be mixed include fluids and suspensions, such as magnetic microparticles in fluid.
Washing device for pipettes and stirrers are known from the prior art in which the devices to be washed are inserted into a cavity filled with wash fluid and the wash fluid is replaced after one or more wash steps. The fluid is usually replaced by removing the fluid through a fluid duct using suction.
A device for washing pipettes is described in European patent application 0 661 542 in which the pipette is inserted into a tube that surrounds the pipette at a distance of 1 mm or less. Fluid is injected into the tube to wash the pipette.
Devices with a cavity known in the prior art have the disadvantage in that the fluid is injected into and emptied from the cavity through the same fluid duct, making it inevitable that used and fresh wash fluid are mixed. Moreover, these devices have the disadvantage that they operate according to a dilution principle. In other words, the fluid that adheres to the pipette is diluted with the wash fluid. Even after the pipette is removed from the cavity. therefore, fluid which is contaminated to a certain extent is still adhered to it. Although this problem is avoided with the device described in EP-A-0 661 542, this device is limited to a certain type of pipette because the duct is designed to accommodate a pipette of a certain diameter. This wash device therefore cannot be used with different types of pipettes or for pipettes and stirrers interchangeably.